CVE-2026-53524

medium

EUVD alias: EUVD-2026-64185

Assigned by CNA: github_m

Published 2026-08-21 · Modified 2026-08-21

Discuss on Community Propose mitigation

CVSS v3

6.5

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS v4 NEW

—

not yet in upstream

VIR risk

6.5

Description

WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 4.3.0 through 4.9.0, the WeeChat relay module's WebSocket permessage-deflate decompression function relay_websocket_inflate() has no upper bound on output size. An authenticated relay user can send a small compressed WebSocket frame (~100 bytes) that decompresses to gigabytes, exhausting all server memory and crashing the entire WeeChat process. The api protocol enables permessage-deflate and requires authentication before WebSocket upgrade. Version 4.9.1 patches the issue.

Predictions

Exploit likelihood

75%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Debian Security Tracker · View original ↗ · DFSG

CVE-2026-53524 NameCVE-2026-53524 DescriptionGHSA-v2v4-45wm-5cr3: Decompression Bomb in Relay WebSocket (DoS) SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) Vulnerable and fixed packages The table below lists information on source packages. Source PackageReleaseVersionStatus weechat…

CVE-2026-53524

Name	CVE-2026-53524
Description	GHSA-v2v4-45wm-5cr3: Decompression Bomb in Relay WebSocket (DoS)
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
weechat (PTS)	bullseye	3.0-1+deb11u1	vulnerable
	bookworm	3.8-1	vulnerable
	trixie	4.6.3-1	vulnerable
	forky, sid	4.10.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
weechat	source	(unstable)	4.9.3-1

Notes

https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3
Fixed by: https://github.com/weechat/weechat/commit/35699ea8025e5bcd37cca2b1c22f041c38b8a624 (v4.9.1)
https://weechat.org/doc/weechat/security/WSA-2026-1/

Home - Debian Security - Source (Git)

Apply commands

text fix

Notes

https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3Fixed by: https://github.com/weechat/weechat/commit/35699ea8025e5bcd37cca2b1c22f041c38b8a624 (v4.9.1)https://weechat.org/doc/weechat/security/WSA-2026-1/

OS impact

Debian Mixed 5 releases

Version	Status	Fixed in
trixie	Affected	—
sid	Fixed	`4.9.3-1`
forky	Fixed	`4.9.3-1`
bullseye	Affected	—
bookworm	Affected	—

References

CWEs

CWE-409

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.